Can you press gas when car is off?
On gasoline, fuel-injected cars, pressing the gas pedal with the engine off will move the throttle plate. Nothing else will happen since the electrical system is off and the engine control module can't signal for fuel injection.
Nothing at all. You may as well be pressing a switch when there's no power to it. But in a car that uses a carburettor, there will be a small squirt of fuel from the accelerator pump each time you press the throttle.
The engine will roar and 98% of the time, nothing will happen. Engines have rev limiters. They are set to something below the actual mechanical limits of the engine to keep people who do stupid things like rev the engine in neutral from blowing up their engine.
The fuel injection system does nothing until the engine is turning (starting or running), so pressing the pedal before you start will make no difference. The fuel injectors work at any RPM, so a choke is not necessary. The computer simply feeds a little extra gas through the fuel injectors to start the engine.
No, revving your engine while you're in park is generally not bad. You can also rev it in neutral without hurting it—just be mindful of how much you're revving your engine, and for how long.
It is possible to damage your car by driving fast, but most of the damage is done through rapid acceleration. Flooring the gas will essentially start a chain reaction of your engine components crashing together. This means that you can damage your pistons, connecting rods, transmission, axles, etc.
This won't damage the car.
If you rev the engine to max and leave it running at max for hours then it will suffer damage, but few do that. ok , so if the gear stick is on "Park" or "Neutral" mode on an automatic transmission car, it won't damage the car if you step on the gas if you just want to hear the engine roar ?
When you rev your engine, you place additional and unnecessary stress on your car and its engine. This is imperative when it's cold outside—revving your engine before it has had time to warm up is especially damaging, as the engine's oil hasn't had sufficient time to circulate and properly lubricate your car.
While acceleration will never damage your engine in the same way as, say, hitting a tree at 60mph, it does cause damage in the long term. Quick acceleration puts a lot more stress on your engine than gentle increases in speed, contributing to engine wear and damage, even if you don't notice the changes right away.
Shifting to neutral from drive while moving will do nothing at all. Assuming this automatic vehicle has a torque converter, when you shift back into drive, the computer will select an appropriate gear for your speed, (usually the one you were just in, unless you've slowed down) and place the vehicle into it.
What happens if I accidentally drove in neutral?
Accidentally shifting into neutral on your car shouldn't cause any damage to your vehicle. And fortunately, nothing should happen to your car if you shift into reverse while driving other than your car slowing down and some grinding of the gears. Newer cars come equipped with a reverse inhibitor.
This subsequently means that the engine is getting less cooling, which can lead to bearing failure due to heat and friction. Secondly, since your car is in neutral, you can no longer accelerate. This means you have lesser control over your car as you can only slow down and not speed up.

Don't Leave the Engine Running
Make sure you put your vehicle in park and turn the engine off before pumping gas. You should also switch off any auxiliary 12-volt power sources such as phone chargers and cigarette lighters because, while rare, they can be a potential igniter of a fuel fire.
Turn Off Your Vehicle
Whether you are just “topping off” your tank or maybe it's 15º outside, leaving your car running when pumping gas can be very dangerous. If any static electricity combines with the heat and vapors being put off from your engine, and with the gasoline in close proximity, fires can start.
When an alternator turns faster, it produces more electricity. Ray: So by revving your engine up to 2,000 rpm or 2,500 rpm and holding it there while the other car tries to start, you're increasing the output of your alternator and giving your battery a little bit of extra power, which it can donate to the other car.
The battery will charge faster if you rev the engine faster. Why? Because the faster the crankshaft turns, the faster it turns the belt that runs the alternator. And the faster the alternator turns, the more electricity it produces to run all the electrical stuff in the car — and recharge the battery.
After all, when redlined, an engine can sound like it's about to blow. However, there's no need to worry. Redlining will not damage an engine or cause it to explode, no matter how cruelly you treat it. Therefore, revving the engine to its maximum speed several times a week is not a problem.
Revving your engine will not make it warm up any faster, but it will subject your engine to increased stress before the oil has had the chance to circulate properly. You should also avoid accelerating too quickly until the engine has fully warmed up.
That's a big misconception. An engine needs to be driven hard occasionally, meaning at freeway speeds and accelerated with a wide open throttle. Under such circumstances, engine combustion temperatures reach a peak and keep the engine clean by burning off deposits.
Generally its a bad idea to just floor the gas. In however, certain circumstances such as open rural interstate roads, opening the valves for a short amount of time can clear engine buildup and make your car breathe a bit more, giving it a bit longer of a lifespan, but only for SHORT periods of time.
Does gas get used when the car is in park?
Does your car continue to use fuel while in park? Yes, your vehicle will continue to use fuel even when you put it in park. While many people idle with their foot on the brake pedal, doing that or putting the vehicle in park are essentially equivalent in the fact that both will use fuel as time goes on.
An idling car uses between 1/5 to 7/10 of a gallon of fuel an hour. An idling diesel truck burns approximately one gallon of fuel an hour. With average U.S. prices for diesel fuel topping $2 a gallon1, that's about $2 an hour wasted.
Experts maintain that your car should never idle for more than thirty seconds to one minute. However, the reasons behind that advice pertain to conserving fuel and limiting the amount of exhaust. A car's engine can idle indefinitely outdoors without any safety concerns.
Consistently redlining your car can cause serious damage to not only your tires, but also your engine. For those with manual-shift modes or manual transmissions, it can be quite easy to redline (whether on accident or on purpose) and eventually cause your engine to wear down prematurely.
It's more often the flywheel — which is the larger gear that the starter gear meshes with. They're both pretty tough, and accidentally starting the car when it's already running once in a blue moon probably will not do any damage. If it's done repeatedly, though, you can wear down or break a tooth on the flywheel.